Pneumatic collet chuck closer



Dec. 2, 1952 E CHURCH 2,620,196

PNEUMATIC COLLET CHUCK CLOSER Filed Feb. 14, 1948 NVENTOR .E. CH CH ATTORNEY Patented Dec. 2, 1952 UNITED STATES PATENT OFFICE PNEUMATIC COLLET CHUCK CLOSER Albert E. Church, New Britain,, Conn., assignor to Union Manufacturing Company, New Britain, Conn., a corporation of Connecticut Application February 14, 1948, Serial No. 8,478

' Claims. 1

This invention relates to collet chucks adapted primarily for application to rotatable machine tool spindles and more particularly to pneumatic means for closing chucks of the collet type.

An object of the present invention is to provide a convenient and simple form of expansible chamber type of closing means for work holding collets, the collet being attached to a member moved in a direction to close the collet when air or gas under pressure is admitted to the expansible chamber formed by a flexible impervious annular member.

A feature of importance of the invention is that air or gas under pressure may be supplied to the chuck by a detachable connection to a flexible supply tube or by a permanent non-rotatable collar which may be mounted rotatably on the chuck and to which an air or gas supply may be connected.

With the above and other objects in view the invention may include the features of construction and operation set forth in the following specification and illustrated in the accompanying drawing.

In the accompanying drawing annexed hereto and forming a part of this specification, I have shown the invention embodied in several collet chucks for application to the work rotating spindle of small machine tools such as lathes, but it will be understood that the invention can be otherwise embodied and that the drawing is not to be construed as defining or limiting the scope of the invention, the claims appended to this specification being relied upon for that purpose.

In the drawing:

} Fig. 1 is a front elevation of a collet type chuck embodying the present invention;

Fig. 2 is a longitudinal central sectional view of the chuck shown in Fig. 1 taken on the plane of line 2-2;

Figs. 3 and 4 are views corresponding to Fig. 2 and showing slightly modified forms of operating means for the collet member of a work clamping and rotating chuck.

In the above mentioned drawing there have been shown several embodiments of the invention which are now deemed preferable, but it is to be understood that changes and modifications may be made within the scope of the appended claims without departing from the spirit of the invention.

Briefly, and in its preferred form, the invention may include the following principal parts: First, a body member adapted for mounting on the end of a rotatable spindle of a machine tool; second, a spring collet member movable axially within the body member and having a tapered portion engaging a correspondingly tapered portion ofthe body member so that movement of the collet-in one direction will compress portions of the collet on a work piece or member positioned within the axial opening extending through the collet; third, a disk detachably and preferably adjustably attached to the inner end of the collet member as by threaded means and slidable within a recess formed within the body member; fourth, an inflatable flexible and impervious member within the body member and having a surface in contact with the disk attached to the collet; and fifth, means to admit air or gas under pressure to Within said inflatable member to force the disk in a direction to close the collet.

Referring more in detail to the figures of the drawing and first to the form of the invention shown in Figs. 1 and 2, there is provided a body member l0 adapted for attachment to a rotatable spindle (not shown). In Fig. 2 a threaded connection is shown formed on the back plate I l for mounting the body member Ill of the chuck on the threaded nose of a machine tool spindle. The body member I0 and back plate H are detachably but rigidly secured together and the chuck extends in alignment with the axis of the threaded connection. Within the body member III is a spring collet member I2 of the usual or standard form. As shown the collet member I2 is split longitudinally for a portion of its length at several angularly disposed positions so that slight longitudinal movement of the collet member 12 will force a conical portion [4 at its forward end into contact with the tapered end of the recess provided in the body member H) for the collet member.

At the inner end of the collet member l2 are provided screw threads 16 for detachably connecting a disk l8 slidable within the recessed portion of the body member ID. Disposed between the forward face of the disk [8 and a wall of the body member Ill is an inflatable impervious member 20 preferably formed of flexible material such as rubber or rubber substitute. As shown this member 20 is in the form of a hollow annulus one side face being in contact with a wall of the body member [0 and the opposite face engaging a side face of the disk l8. By inflating the impervious member 20 the disk 18 is forced in a direction to correspondingly move the collet member 12 in a closing direction. To return the disk l8 and collet member I 2 to their open position one or more springs 22 may be provided.

To admit air or gas to the interior of the member 20 a collar 24 may be mounted for rotation around the forward end of the bodymember [0. One face of the collar 24 bears against a forward face of the body member In and is held in position against said face by a nut 25 threaded over the forward threaded end of the body member. Between the collar 24 and nut 26 may be provided an anti-friction bearing 28 to reduce friction. Also to maintain a pressure tight seal between the body member I and collar 24 an annular flanged sealing ring 30 may be housed in mating grooves in the body member: and collar.

An air or gas supply connection 32 is attached to the collar 24 and a conduit leads therefrom to the groove for the sealing ring 30. The. seal-- ing ring 30 is perforated at this point so that air or gas may enter the inflatable member 20- through a short nipple 34 of any usual'type in alignment with the perforation in the ring 30. As shown in Fig. 2 the sealing ring 30 is: provided within the annular groove in the collar 24 with peripheral flanges on its inner and outer edges, these flanges engaging the walls of the groove within the collar 24 in pressure tight relation while permitting rotation of the collar relative to the body member. By admitting air or gas under. pressure to, the connection 32: the inflatable member 20 will be extendedto force the disk I18 and collet. member. I2 in a direction to close the collet. By opening the connection 32- to atmosphere and releasing pressure within the inflatable member 20 springs 22 will force the disk I8 and collet member I2 in a direction to open the collet. To prevent rotation of the disk t8 within the body member ID and to permit adjustment of. the collet member I2 a stud. 36 may be positioned. within the back plate I I ofthechuck and entering an opening within the disk I8. 'I-o adjust the position of the disk- I8 on the threaded end of the collet member it is only necessary to rotate the collet I2 in thev body.v member In by means of a tool inserted in openings in the. front face of the collet.

The modified form. of the invention shown in Fig. 3' has a body member 40, collet member 42 and disk 44 similar in every way to the corresponding parts shown in Figs. 1 and.2. The back plate however is provided for attachment to a different form of spindle. This back plate as shown is provided with acentral tapered.- recess 50 and with a plurality of cam locking studs 52 .but one of which isshown.

To admit air or gas'under pressure to. the inflatable member 54 a collar SGisrotatablymounted on the outside cylindrical surfaceof. the body member 40. A sealing ring 58. positioned withman annular recess in the periphery of the body member 40 hasits flanges engaging the sidewalls of a circular recess in the collar 56.. A, supply connection 60 leading into the collar 516 permits air or gas under pressure. to be admitted to the groove in the collar 56 and through a tubular connection 62 within the body member 40 through the disk 44.and.to -the interior of the inflatable member 54.. Nipples.6.4.and;.66. at opposite ends of theconduit-maintain. pressure tight connections betweenthe collar 56.and inflatable member 54-. As the movement. of 'the disk 44' is relativelyslight. and, the tubular connection 62 relatively long, movement. of the disk will. flex the connection very slightly. The, disk 44- may be retained against rotation within the chuck and move in a direction to open. collet bymeans similar to those shown in Fig.2.

The modified form of the invention shown in Fig. 4 is similar to that shown in Fig; 3 except for the connection 'lflyto admit airor gas under pressure to the inflatable member I2; In this form of the invention a supply nipple TIlfor the inflatable member 1-2 is extendedto the outside surface of the. body member so that asupply-connection can be attached temporarily thereto whenever it is desired to inflate the member 12. Within the nipple H! is a self-closing valve-T4 4 to retain the pressure within the member 12 until the valve 14 is manually opened.

I claim as my invention;

1. A collet chuck closing means comprising a rotatable body member, a collet member therein, a disk mounted on the inner end of said collet member within the body member, an inflatable member within said body member and means to admit fluid under. pressure to said inflatable member during rotation of said chuck to force said disk and collet member toward closed position.

2. A collet chuck closing means comprising, a rotatable body member, a collet member extending therein, a disk within said body member and attached to the inner end ofsaid colletmemher, an inflatable member within said body member having a portion thereof in contact with said disk, and means to admit fluid under pressure-to said inflatable member during rotation-of said chuck to force said disk in a direction to. move said collet member to itsclosed position.

3. A collet chuck closing means comprising a rotatable body member, a collet member ex- .tending therein, a. disk within said body member and adjustably attached to the inner end of said collet member, an annular inflatable member within saidbody member disposed between said disk and a wall of said body member, andv means toadmit. fluid under pressure to within. saidv inflatable member during. rotation. of said chuck, to

force said disk in a direction to, movesaid collet to its closed position.

4. A collet chuck closing means comprising a rotatable body member, a collet. member extending therein, a disk within said body member and attached to the inner end of said collet. member, an annular inflatable member within said body member surrounding said collet member and disposed between said disk and a wall of said body member, and means to admit. fluid under. pressure to within said inflatable member during rotation of said chuck to force-said disk inv a direction to movesaid collet. member toits closed position.

5. .A collet. chuck closing. means comprising a rotatable body member, a.collet.member. extending therein,,a disk. within said. body member and attached to theinner end of said collet. member, an annular inflatable member withinsaid body member surrounding said collet member and disposed between said diskand a wall. of, said. body member, a collar rotatably mounted.' onsaidi body member, a fluid. supply connection tosaid collar permitting continuous admission of fluid under pressure to said inflatable bag, and pressuretight conduitsbetween said collar and saidv inflatable member during rotation of said chuck, whereby when an under pressure is admitted; to. said. inflatable member said disk will. be forced. in a direction to-move said colletmemberto itsclosed position.

ALBERT E.. CHURCH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITEJJSTATES PATENTS 

